Conventionally, there is known a heat exchanger, which is made of two heat exchangers, which are used differently. Such a heat exchanger is proposed to have a first heat exchanger, which is configured to have tubes and fins between a pair of tanks, and a second heat exchanger, which is also configured in the same way as the first heat exchanger, both disposed in parallel to each other and integrally connected to each other as described in, for example, Japanese Utility Model Publication No. Hei 6-45155 and Japanese Patent Application Laid-Open Publication No. Hei 7-332890.
Japanese Utility Model Application Laid-Open Publication No. Hei 2-54076 proposes a heat exchanger having a first heat exchanger and a second heat exchanger which are formed into one body, which is configured by stacking flat plate fins, connecting to communicate a plurality of tubes with the plate fins, connecting ends of the tubes to an end plate configuring a tank, and assembling a tank plate to the end plate, wherein the end plate and the tank plate are separately formed or the tank plate is separately formed.
There is also known another heat exchanger, which is produced with two different heat exchangers assembled in series vertically or horizontally. As described in, for example, Japanese Utility Model Publication No. Sho 59-16692 and Japanese Utility Model Application Laid-Open Publication No. Hei 2-36772, there is proposed a heat exchanger which is in a single form structurally but actually has two heat exchangers by disposing tubes and fins between a pair of tanks and a partition plate at the midpoint of the pair of tanks.
Such a heat exchanger has the tanks and tubes to form a heat exchange medium passage and the fins to form an air passage. And, a heat exchange medium supplied from the tank is flown through the plurality of tubes to make heat exchange with the exterior by means of the fins.
The fin is formed to have a corrugated side view with the same pitch by passing a flat fin material through gear-shaped rolls, which are vertically disposed in several sets to shrink the fin material in a longitudinal direction or to compress it. And, in view of improvement of the heat exchange rate and an airflow resistance, the fins are generally formed with louvers on surfaces thereof, and the louvers are formed by the rolls when the fins are formed into the corrugated shape.
In the conventional heat exchanger formed by combining two heat exchangers, the fins disposed between the tubes are often integrally formed and disposed in the first and second heat exchangers. But, the individual heat exchanger has different use, performance and requirements of different heat radiation degrees and airflow resistances. Therefore, where the fins are formed to conform to the performance of one of the heat exchangers, the heat exchange rate of the other heat exchanger is lowered.
Accordingly, the fins connected to the first heat exchanger are separately formed from those connected to the second heat exchanger. But, it is not desirable to form the fins separately for the first and second heat exchangers because the number of parts increases and workability becomes complicated.
In view of the above, the present invention aims to provide a heat exchanger which can have an improved heat exchange performance with the above-described disadvantages remedied without forming the fins separately for the first and second heat exchangers.